[unreadable] [unreadable] The goal of the proposed research is to develop new proteomic signatures of lymphoid malignancy. Genome-wide transcriptional profiling of resting or proliferating normal B cells and proliferating malignant B cells identified two major axes of gene expression: one group of genes significantly differentially expressed between resting and proliferating normal cells (a "proliferation signature", and another group of genes differentially expressed along an orthogonal axis unrelated to normal proliferation (a "cancer signature"). Transcriptional signatures of lymphomas establish a basis and justification for the proposed work; proteomic signatures of lymphoid malignancy are required in part because messenger RNA-based signals are not a perfect proxy for protein-based signals. Preliminary studies establish our ability to perform extraction of lymphoid tissue samples of murine or human origin, for 2D PAGE separation, followed by mass spectrometry (MALDI and LC-MS/MS of tryptic peptides) and proteomic identification of potential biomarkers for lymphoid malignancy: a "malignancy proteome". Our preliminary results support a central hypothesis: resting and mitogenically activated, normal lymphoid cells provide a framework to interpret malignant proliferation. The proposed research will be conducted under a single Specific Aim, with two subordinate sub-Aims. Sub-Aim 1: Define proteomic 2D reference maps for resting, activated and malignant transgenic B cells taken from mouse spleen. Sub-Aim 2: Employ similar methods to investigate the malignancy-specific signature of human primary tissue from patients diagnosed with lymphoid malignancy. We expect to learn that a relatively simple set of protein biomarkers defines proliferating malignant B cells, distinct from proliferating normal B cells. Based on our results so far, we expect that the boundary conditions of normal resting lymphoid subpopulations and the same subpopulations after in vitro mitogenic activation provide a useful heuristic to interpret the induction of B cell proteins that are unique to the malignant state. This approach greatly simplifies proteomic biomarker discovery for lymphoid malignancy. The heuristic should be adaptable and extendable to a wide spectrum of human hematologic malignancies, including myeloid leukemias. [unreadable] [unreadable] [unreadable]